Coal pulverizer



Dec. 3, 1929. F. G. LUGRIN COAL PULVERIZER Filed Jan. 5, 1928 2 Sheets-Sheet llyvelyfor y Dec. 3, 1929. F, LUGRIN 1,737,931

COAL PULVERIZER A Filed Jan. v,5, 1928 2 sheets-sheet 2 Patented Dec. 3, 1929 PATENT OFFICE FRANK G. LUG-RIN, OF MOOSE JAW, SASKATCHEWAN, CANADA COAL PULVERIZER Application led January 5, 1928. Serial No. 244,742.

The invention relates to improvements in coal pulverizers and particularly to improvements in that type of pulverizing machine at present known on the market as the Unipulvo -unit coal pulverizer and an object of the invention is to provide means for controlling the amount of air admitted to the pulverizing chamber of the pulverizer to miX with and carry in suspension the pulverized coal and also to means for admitting and controlling air to mix with the pulverized coal in suspension and passing to the furnace, such latter air supporting combustion in the furnace.

With the above more important objects in view, the invention consists essentially in the arrangement and construction of parts hereinafter more particularly described, reference being had to the accompanying drawings, in which Fig. 1 is a side View of the pulverizer.

Fig. 2 is a front view thereof.

Fig. 3 is a vertical sectional view through the pulverizer.

Fig. 4 is an enlar ed detailed vertical sectional view at 4 4 igure 3.

Fig. 5 is a vertical sectional view at 5-5 Figure 4.

Fig. 6 is an enlarged detailed horizontal sectional view at 6 6 Figure 2.

In the drawings like characters of reference indicate corresponding parts in the several figures.

The machine as herein shown with the eX- ception of the air admitting and controlling devices provided is as at present found on the market under the name Unipulvo unit coal pulverizer and as the said machine is well known and understood by those familiar with the art, it is not considered necessary to herein give a detailed description of the various well known parts.

In such pulverizer, the raw coal 1 is stored in the hopper 2 and is crushed by the rotating crusher 3 which reduces the lumps to a size which can be uniformly fed to the pulverizer. A driven coal feeder 4 is adjustable for any desired capacity to the full rating of the machine and the crushed coal is fed by the feeder into the grinding chamber where it is pulverized by the action of a driven rotor 5 and a grid 6, the direction of rotation of the rotor being as indicated by the applied arrow Figure 3.

A Skimmer type separator 7 is located in the upper part of the apparatus and the finely pulverized coal is drawn from the pulverizing chamber upwardly through the passage 8 to the separator 7 the pulverized coal being sus-V pended in air admitted to the pulverizing chamber in a manner later described. After passing through the separator 7, the pulverized coal suspended in the air enters the pipe 9 which leads to the fan casing 10 wherein a fan of any approved type discharges the suspended pulverized coal into the pipe 11 which leads to the furnace where the same is to be burned. The fan and the rotor 5 are driven by an electric motor 12. The pipe 9 is provided with a damper 13 which can be regulated as desired. An air inlet pipe 14 leads to the pulverizing chamber and in this connection I might remark that this air is preheated to a temperature of say from 180O to 1900.

The machine as above described is as now marketed and in such a machine there is no provision made for regulating the air admitted through the pipe 14 to the pulverizing chamber to control the velocity thereof and as the velocity of the air passing through the pulverizing chamber and up the passage 8 controls the size of the ground particles of coal which will be suspended in the air, it is desirable to have a means for governing the velocity of the air and such means forms part of my invention. I might say that when such a type of machine with no air control for the pipe 14 is working up to say its capacity, a very large amount of air is drawn into the grinding chamber and the velocity of the air is so great that it lifts coal particles much too big to burn in suspension with the result that the eficiency of the machine is impaired.

By regulating the quantity of air admitted through the pipe 14 to the grinding chamber, I can regulate the size of the ground coal particles which the stream of air will carry with it, such obviously being dependent on the velocity of the air through the chamber. With my air regulation, the velocity of the air under all working conditions will be regulated so that very fine coal dust only will be carried through the pipe 9 in suspension to the furnace.

The particular details of the valve 16 employed for regulating the amountot air passed to the grinding chamber are of no particular consequence although I have utilized to good advantage a valve of the grid type embodying a stationary slotted plate 17 crossing the pipe and a sliding slotted plate 18'operating over the plate 17 and controlled by the manipulation of a hand Wheel 19. Obviously as the slots are passed into and out ott registration, a greater or less amount of air Will be admitted through the pipe 14 to the grinding chamber.

It is desirable also to have suiiicient air mixed with the coal dust passing from the pulverizing machine to the furnace through the pipe 9 to support combustion in the furnace and with this in view, I provide a pipe 19 leading from the pipe 14 in a location at the outer side oi the valve 16 to a distributing chamber 20 surrounding the pipe 9. rlhe l pipe 9 is slotted as indicated at 21 at intervals all the Way around to permit the air to passfrom the chamber 2O into the pipe and effectively mix with the passing suspended coal dust going to the furnace. A valve 22 is inserted in the pipe, such being herein shown as in the torni of a sliding damper which can be pulled in or out as occasion demands to control the amount of air passing upwardly through the pipe 19 to the pipe 9 to mi); With the suspended coal dust.

The valves 22 and 10 Will be both regulated to give the most eiiicient operating condition depending on the turnace capacity required and as aforesaid, the regulation Will be such that under all Working conditions only very tine coal dust will be carried in suspension to the furnace.

What I claim as my invention is 1. In a coal pulverizer, the combination With the pulverizing chamber and independent air inlet and air outlet pipes to and from the said chamber, of an adjustable valve introduced in the air admission pipe and a valve controlled pipe leading from the air admission pipe to the air outlet pipe.

2. Ina coal pulverizer, the combination with the pulif'erizing chamber and the air inlet and air outlet pipes to and from the said chamber, of an adjustable valve controlling the amount of air admitted to the pulverizing chamber through the inlet pipe, a distributing chamber surrounding the outlet pipe and provided with a series of air inlet openings connecting the interior of the chamber with the interior of the latter pipe, an air supply pipe connecting the chamber with the air admission pipe and a valve controlling the passage of the air through the air sup- Ply Plpe- 3. In a coal pulverizer, the combination With the pulverizing chamber and the air inlet and air outlet pipes to and from the said chamber, of a manually operated valve mounted in the air intake pipe and controllin the amount of air passing to the grinding c amber, a mixing chamber surrounding the outlet pipe, said outlet pipe being provided circumferent-ially With a series of holes forming a communication between the chamber and the interior of such pipe, an air sup ly pipe connecting the mixing chamber With the air inlet pipe and opening to the same to the outer side of the valve thereot1 and an adjustable valve. for controlling the amount of air passingv to the mixing chamber through the air supply pipe.

Signed at Moosejaw, Sask., this tenth day of September, 1927.

FRANK G. LUGRIN. 

